parE (Escherichia coli K12): DNA topoisomerase IV, subunit B; Topoisomerase IV is essential for chromosome segregation; it is the principal protein responsible for decatenating newly replicated chromosomes. It relaxes supercoiled DNA. MukB stimulates the relaxation activity of topoisomerase IV and also has a modest effect on decatenation. Belongs to the type II topoisomerase family. ParE type 1 subfamily.